Circuit arrangement for mixing oscillations



Dec. 7, 1948.

E. C. CORK ET AL CIRCUIT ARRANGEMENTS FOR MIXING OSCILLATIONS MICHAEL BOWMAN -MANIFOLD.

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w .HDWPDO h H I N VENTORS. EDWARD C. CORK.

FREDERICK H. GALE.

ROY BLYTHEN.

HADAUHW ATTORNEY DMSHWUNM Patented Dec. 7, 1948 I @flaisassr p CIRCUIT ARRANGEMENTFoR MIXING I OSCILLATIONS 1 I Edward Cecil Cor-handMichael liowrnan Mani- I I fold, Ealing, London, Frederick Henry Gale Hillingdon, and Roy Blythen, Norwood Green, .Engl and, assignors to Electric &; Musical Industries LimitedgHayes, England, a company oi.

-I- Application sharia, 1945, s m1 No. 58a,20o

In Great Britain September 1 1942' Section 1,PublicLaw ssofaiigusts, 194s Patentexpires September 1; 1962 This invention relates to circuit arrangements for mixing oscillations of high frequencies,.such circuits being suitable for use *in receivers of the superheterodyne typ I I I I The object of the present invention is to provide a convenient arrangement of' 'mixing cirr cuit which is suitable for use in conjunctionwlth waveguides; I I

According to theinvention there isprovidedia circuit arrangement formixing electrical oscil conductors therein feeding one of flsaidoscilla tions to one terminal Iof said element and the other of said oscillations to the other terminal I I of said element, thearrangement forming a coaxial line section with said element coupled between adjacent ends of said inner conductors. I Preferably the mixing element isoi the crystal typealthough other deviceshavingnon-linear characteristics maybe used, suLch ajsldiodes.

One or both of the terminals or coupled ends of said element may be connected to a further coaxial line section or sections provided with an adjustable piston or pistonsfordmpedarice matching purposes. The inner conductorof said further co-axial line sectionor of one of said sections may serve as the output lead for the resultant oscillations, the piston associated with this lead being constructed to provide a capaci tative short-circuit -for'- the high irequency oscillations. I

In: order that the stricter/entice may beiclearly' If understood and readily carried into "effect; it will now be more fully described with reference to the accompanying drawing which illustrates in longitudinal section a circuit arrangement constructed. in accordance with the preferred form of the invention.

As stated above, the invention is of particular use as the mixing circuit of a superheterodyne receiver in which the signals are transmitted via a wave guide to the mixing circuit where they are mixed with local oscillations. As shown in the drawing, the reference numeral I indicates a portion of a wave guide along which the signals are transmitted, the wave guide comprising an outer conductor and the signals being conveyed along the air dielectric of the guide. Inthe preferred form of the invention shown the detector is of the crystal type indicated by the reference numeral 2 and forms a continuation of the centre conductor of a coaxial line which is coupled to tonn s. (01. 250-40) the wave guide I. The coaxial line comprises an inner conductor 3 and a surrounding tubular conductor 4, the end of the conductor 4 nearer the wave guide I being connectedto and support- 5 edin a conducting disc 5inturnconnected to and supporte-d by the wave guide I. Thesig'nals transmitted along the wave guide Ifare collected by a disc G which is connected to a tubular conductor 1 iorming part} of the inner conduc- 1 m tor land into which the inner conductor 3 prolations of high frequency comprising a mixing I element for mixing saidoscillations, a =tubular conductor in which said element isdisposed and supported, said tubular conductor having inner jects so as to be incontacttherewith, the tubular conductor] being supported in the outer conductor l by an insulating block 8. The disc 6 and'the tubular conductor T can be adjusted 15 axially relatively to the guide lW The outer coni ductor 4 co-operates withtheleft-hand end of a conducting sleeve S forming part of the outer conductor; the sleeve 9, together with the inner conductor"3 are capable of axial movement zopwhereby the coaxial line comprising the conductort'sleeve 9 and conductors 3 and 1 are thus of a telescopic construction for impedance matching'purposes, The inner conductor 3 is con'r'iectedto a rod lll which forms the inner conductor of further coaxialline itheouter tubular conductor of whichis indicatedat H and is generally arranged-at right anglesto the 00- axial line formed bythe conductors 3 and 4. The rod I0 is supported atits upper endin the outer "conductor I by a block of insulating material Ha, the rod" l0 thusserving to support the innerconductor 3 and oneend of the crystal detector Z. Theotherendofthe detector? is supportefdgbya further rod Il2,which also forms the inner conductor of a further portion of coaxial line, theputer conductor of which is indicated at I3, this line also projecting at right-angles to the inner conductor 3. The upper end of the rod I2 is supported by a metal block I4 in the outer conductor l3, this metal block forming a short circuit between the rod [2 and conductor l3.

The local oscillations to be mixed with the signals fed to the detector 2 via the conductor 3 are applied to the detector via a further portion of coaxial line telescopically associated with the right-hand end 16 of the sleeve 9. The further portion of coaxial line comprises an inner conductor l5 and an outer conductor 20 supported in contact with the sleeve 9 by an insulating block I9. The local oscillations are fed to the detector 2 via a capacity coupling comprising a disc 11 connected to theinner conductor l5 and another disc 18 connected to the rod l2. The further portion of coaxial line formed by concoupling can be adjusted. An aperture 2| is, H

provided in the sleeve 9 as shown, to permit reondisqex el n -m d d ith n dim r-I- condudtoaaxiallwspaoed fromathe inner; conductor of the first coaxial line, a source of local oscillations coupled to said inner conductor of the secplacement of the crystal. In usathis taperturelt5 qlliiwqqfililpl;1ine; a -rnixing element electrically will be covered by a metallic plate.

In order to adjust the coaxial line formed by the conductors I2 and I3 for impedance; gnatchg ing purposes a short-circuiting pistog ggiispro: vided arranged to slide relativelxtggthe con ductors I2 and I3 and to be clampe d infltheadII- justed position. Further, for the purpose of adjusting the coaxial line formed by the conductors I0 and I I in order to permitthe passage of the intermediate frequency signals but to 'pre vent the passage of high frequency:signals algp g the conductor III, a further short-circuiting ton 23 is provided associated with the coaxial line I 0 and I I, this short-circuiting pistombeing capacity-coupled to tlie conductor II] by the 20 p ovision-I ta I1 av iI-rdie ec no 24 Ieatteched t the ;pi QrA':, :3-- hismis on. an; elsebeclamped. in iti diu edI--pesit Qn=.: I I With-the ns l tioasho ,si na s me ted up. el d -tq onelt mm l sndao thecmstsl z-lan th locelno cil t ns I ene Ied-II-te: ez onesite tor.- minal or; endor the crystal via-the .vcapacityicou-v p ne1 l' l.- l8 theint rmed atefre encies-si nals ss ng; Q I te mQQia Qr nequ nc ampl fiers-mot shown) =alpng the rod l-q whic thusIformsetheenm i ei y. outi: .ut-I 1 ed. Toeom st uc ion:desq b drpetmit qo theI QoatiQn-of the detector; inside the (outer ce duet or--of 9a Iii-mans:

s iom ine so astofqr. ffect velx B/Icontinuar connect d between the adjacent ends of said two inner conductors, and means coupled to one of t saidylnn er conductors-for deriving a frequency r esu lting fromthernixing of said signal and local 0:1 osc 1letlaos-..

I 2., The +eqxnbination; defined in claim 1 wherein said mixm element is constituted by a crystal rectifier.

31' ii-circuit; arrangement according to claim 1,

wherein one endof said mixing element is con ZQQ QQQtO aIfunthencOaXiaI line section provided witl sag adg-ustalgle piston for tuning purposes.

4. A ci r cuit arrangement according to claim 1, wherein both ends of said mixing element are connected each individually to an additional coaxialolinesection having arr-adjustable rpistonfor i 'lPMRQSQfi-E:

515A circuit; arrangement according toclaim 1-,

wherein one end of said mixing I elementis- Q0117. 5 nected: tel a-.ifunther=I coa xial-- line Isection provided with: an adiustable piston iomtunin :pu p es, d:

wherein, theI inner -conductor l-ofiksaidfurther co axial line section is arranged to serve as, the vout.- put;lead=forvthe mixed oscillations.

necbedrtmaefuitbhfir coaxial ,linecsection' provided-Ir; with: anI-adiustame. piston for tunin I p rpose and the inner-conductor; of -said; further coaxial;

t10I1II-0f h 1.6 qn llefi vqf t e-diner. It has (:35 {line.sectiomiaarrenged toserveas'theIoutputlead:

b n iqund thatrthetieedine o ;II-ttie sisna1s and; QilIati lS tobe mixedt menosir-tenmioels or endsofI cry tal;isIa;ear icule slxa -dymtssequs;

turers noe hea neement tou dr ib Ho tiv 1 91 morew a. the o iliredr-l mesdancew m tch can he,-inorelneadil I-obtained compare i h other-co str ions I rmnseme tdesc ibc hasnheeee e isnedw f use withsisnels-t iensmi ted aloaefthes I I ,t e .Em mq but tw lllbera ms e e he. e.in eo o ristnqt-Ilimi ed lathe ealest;- Sine h, suitable sllslitmcdiflqatioa in entice I n. be mnlox d ,witli nersa ransmittedml t er Qdes,.. uQ.h as the Iimo flu-mode Whatwe claim is z,

I I I 5 I11. c mb nat on a, Iw i I uid sawing I e s nal-modulated oscillations, T a coaxial, ,linei come. .I p in an uter .condue qnsun orted byet WW I s i e 't n nd thereo a d an. imra ondnet n extendin in qthe-waveeui.de tsaidoneemi to rec iv n s id. sisiial m oulatedl,o cillat ons a:

Number for-e the ii-mixed; oscillation and the piston asso-I.

ciatediwith: said output leadgis. constructedtopro: I vlde;aIoapaciizatlveshentecircult' for the high ire:

u ncycoscfllatinns; I

I memoirs-emu 'ilhevfoi-lowine; references are of I record in then.

file: 01 'this patent Z Date v Name. .QI ZJ6 fiouth o t e-l- I-s-s-I-+Feb ,1931% I ,14 I59 Iso thwo hi t a1. an...3I-, 1939;- 2,227,604 Smith Jan. '1, 19,441; I I..2,3a2, 93 ,pellenbach et a1. Aug. 14,1945,

2-: 6=i A circuit arrrangement' 'accordine-to cla m whenei-nrone endz'ofsaid mixing-element is con- 

